Continuous contact filtration



Oct. 23, 1951 E. v. BERGSTROM ETAL 2,572,433

CONTINUOUS CONTACT FILTRATION 3 Sheets-Sheet l Filed NOV. 2, 1949 f NlOct. 23, 1951 E. v. BERGSTROM ET AL 2,572,433

CONTINUOUS CONTACT FILTRATION 5 Sheets-Sheet 2 Filed Nov. 25, 1949 Oct.23, 1951 E. v. BERGsTRoM ET AL 2,572,433

CONTINUOUS CONTACT FILTRATION 3 Sheets-Sheet 3 Filed Nov. 25, 1949Patented Oct. 23, 1951 UNITED STATI-Es Para NT CONTINUOUS CONTACTFILTRTON Eric V. Bergstrom, ;Short f-Hills, vzandr..Greorge.2 J.

Visconty, Clarksboro, N. J .",assignors to Snoopy- Vacuum Oil Company,Incorporated, -a ycorporation of New York Application November 25,1949-;SerialNo 12299152 2 Claims. (Cl..1r 96v- 147) ingithe,rparticularA apparatus :and process @set forthzinfFiglur-e V1... .f.iFiguresB is aadiagrammaticflsketch showing-.the.relationshipofatheelements of ai coninuous con- 5.tactiltration-process, 4thefelements being-represented in block form.

.Q,Intthe:contactI itratonprocess forgdecoloriza'- tion, etc. such.aspthe;decolorization .oftpetroleum oils, for example, pulverizedcontact materialis The Vmaterials generallyused as thepulverized 1-0admitted to avessel containingvtheloil- @The mX- or powderedadsorbentare clays -such as fuller's earth, silica -gels,bauxites,montmorillonites, ac-

tivated charcoal,-and certain -synthetic associations ofsilica'and-alumina to. Whichother-materials, such as certain-metallicoxides, may bei; .5

added. This Ymaterial 'should be pulverized to -a grain -Ysize whichwill-pass through a 100 VVmesh Tylerscreen-and preferably within therange-of about C-400 mesh size.

In these filtration processes-the powdered-material becomes fouledby thedepositionl of carbonaceous material and oily constituents upon` itssurface. By the use of solvents-such'asnaphtha, low .boiling Lalcoholsand ketones; some Aof the contaminantsl can be removed, but theYoperation is too costly -and ineflicient toV be considered commerciallypractical. The usual custom in this art is to subject `the spentadsorbent material to a combination of steaming and naphtha washing toeffect removalofthe oily constituents from the adsorbent, afterfvvhichthe naphthavmay-be distilled off in `a -rotary drum kiln followedbyburning of `vthe contaminants in -anotherme chanicallydriven kiln. Thislprocedure has vvnot proved satisfactory, partly becauseof the high heatcostinvolved in distilling the naphtha from the adsorbent particles.

The object of this invention is to provide an improved continuouscontact filtration process.

A further object of this invention is tovprovide a method for usingfluid drying principles in a continuous contact filtration processwithout losing any substantialamount of solventorl contact material.

These and otherobjects of this invention will be made apparent -by thefollowing Adescription read in View of the attached drawings, in which;I

from .use in afltrationprocess, and incorporat. V'55 ture is agitatedto. assure ,even distribution -Iof `the contact, material inztne oil.'headsorbent Aparticlespick up the objectionable material'from the oil,andthe filtered loil is removedqcontinuously from;the.,vessel. Wl1en=the particles of adsorbent becomefouled t0* the vextentthattheirlteringr efficiency is `reduced materially,` they are `removed Vlfromthe,--vessel. The fouled contact material) ispassedi through f one, ormore-solvent Zowashing,.andltering-steps. and is ,then introduced into.the-apparatus shownon Figurel 2.l described. herebelow. .Referring"now, to`A Figure 2, contact` material from thenaphtha filterispassedthrough conduitv II to Vthe pressure sealconveyor II.

The conveyor, of .the nRedler,typeppermitsithe maintenance of a.pressure differential between its en-` trance and exitand. isi readily'adaptable to contact. filtration-process, although` other suitableconveyors Vare available.

The contact material L is fedflthrough conduit I2 .from the conveyorII..into.k the dryer I3..:.The dryer I3 `maysuitablybeavverticallycmounted vessel of circular crosssection. .Steami isyintroduced into the loWer..-section lofthedryerl I3,

across vthe bottom of .the Avessel-to -provide more 'evendistributionfasv-shownfonFigure 1. Orifice means I5 maylbe installed in-theconduitsIf-to increase the Velocity of Cthe `steam, hereby providing`better-mixing-in I-theldryer. 1The steam has adual purpose-inthatiniad'dition to providingk support :f or lthe contactmaterial it facts:as a .stripping uid, removing :some of the more yvolatile materials fromthecontactmaterial. Of course -thefsteam admitted to Vthe-dryer I3 50through ltheconduits FMLmay be suiiiciertlylhot to impart at leastsomeof -the heat tothe lcontact material to Avolatilize some of theheavier oily-constituents on the surface thereofwniad- "dition. vaheating coil "I5 is located near the lbottom oftherdryer-I3fto-prvide-'heat when 'across the cross-sectional area ofthe vessel. alternate or concomitant supply of combustion `through theconduit 43. -through a suitable air heater 44 and through the 3 Steam isadmitted through the coil I5 by means of the steam conduit I6, theamount being controlled by the valve I1. But the major source of heat inthe dryer in this invention is from the heating coils I8 located in thelower section of the dryer. The source of heat for the coils I8 will bedescribed hereinafter. The coils I8 may be coiled tubes or a bank ofconduits, adapted to provide suitable heat transfer. The steam andvapors within the dryer may be removed from an outlet near the topthereof through a conduit I9.

The dried contact material is removed from the bottom of the drierthrough the conduits 32, 32. Vibrators 33, 33, or other suitable means,are installed in the outlet conduits 32, 32 to prevent packing orbridging of the contact material therein. The ow of material in conduits32,

32 may be controlled by valves 34, 34 but is norconduits by the blower49, controlled by the valve The regenerator 31 is a vertically mountedvessel of circular, rectangular or other suitable cross section. Thecontact material supported -by the lift gas is admitted to the bottom ofthe regenerator through a multiplicity of conduits 42, 42, located todistribute the material equally An supporting gas is provided fromblower d The gas is passed conduit 45, to ano ther. group of entranceconduits 4S, 46 also equally distributed across the bottom vof theregenerator 31 to provide improved distribution.. The gas ilowin thisline is controlled by the valve 4I. -31.is described in more detail inthe copending application for Letters Patent, Serial Number"95,7l3,.filed May 27, 1949. Heat is extracted :from the regenerator 31by passingI a cooling fluid rIhe operation of the regenerator through aheat exchanger located within said vessel. vThe heated cooling fluid isthen passed :through the exchanger I8 located in the dryer to providethe major portion of the heat required to dry the contact material.

.; The regenerated contact material is removed vfrom the regenerator 31through the conduit 10,

as previously described. The regenerated conltact material is separatedfrom the gas by a method fully disclosed in the copending applicationfor Letters Patent. The separated, re- ;generated contact material isthen returned to the contact filtration process for reuse.

Referring now to Figure 3, the sequence of the steps of a completecontact filtration process is shown with the major elements indicated inblock diagrammatic form. From the naphtha filter 96 :the contactmaterial is passed to the conveyor II through the conduit I Il. From theconveyor ,I I the material is passed to the dryer I3 tln'ough n theconduit I2, as previously indicated. The

material from the dryer I3 is introduced into the The contact material,after retus such as the separator 1I and accumulator 14. The contactmaterial is thereafter brought into contact with the oil in the treatingstep and the fouled contact material is withdrawn from the treating stepand returned to the naphtha lter 96.

This invention is concerned primarily with the method of recovering thefines Iand solvent removed from the dryer I3 with the steam used tofluidize and strip the contact material. In order that this continuouscontact filtration process be commercially feasible, it is essentialthat the contact material and solvent be recovered and returned to thesystem in an economical manner. The method of accomplishing this aim isshown diagrammatically on Figure l.

Referring to Figure l, the fouled contact material from the treatingstep is introduced into the lter 9B where it is Washed with naphthaadmitted through the conduit 98. The Wet contact material is withdrawnthrough the conduit I0 and conveyor I I. The contact material,discharged from the conveyor I I, is introduced into the top of thedryer I3 through theV conduit I2. Steam is introduced into the bottom ofthe dryer through the conduit I4. The velocity of the incoming steam iscontrolled to maintain the contact material in the dryer in ebullientmotion. The steam and naphtha are removed from the dryerthrough theconduit I9. In addition, a small portion of the contact fines areremoved with the gases, entrained therein. The gases and entrainedcontact material are introduced into the cyclone separator I I2. Thegases, substantially freed of contact material, pass overhead throughthe conduit II3 to the upper section of the quench condenser 2U and theseparated contactmaterial is withdrawn from the bottom rof the cycloneseparator I I2 through the conduit I I4.V

Within the quench condenser 29 is located a series of verticalheat-exchanger tubes, 3 connected to upper and lower tube sheets 4, 5. Acooling fluid, such as water, is introduced through the conduit l2l intothe space surrounding the tubes and the fluid is withdrawn from theupper portion of the condenser 20 through the conduit 22. The gases,passing downwardly through the tubes of the heat exchanger, are cooledand condense to form, for the most part, liquid naphtha and water. Asmall portion of the contact fines are carried over from the cycloneseparator and tend to settle out on the walls of the condenser tubes,thereby reducing the cooling efficiency of the tubes. A header29 lislocated in the upper portion of the quench condenser 20. The header 29is equipped with a series of orifices adapted to spray liquid naphthaslurry, described hereinafter, into the interior of the tubes to washdown the settled c ontact material and improve the condensing efciencyof the quench condenser. The vapors, converted to liquid water andnaphtha, for the most part, by the cooling action of the condenser,settle in the bottom of the separator 23, which is constructed ofmaterially larger cross section than the condenser to permit settlingand separation to occur. The separator 23 is located directly below thequench condenser, and communicates therewith. The liquid level in theseparator 23 iscontrolled'by operation of the valves 24 and 25 at apredetermined level, adequate to provide efficient separation. Thenaphtha, being lighter than the other material, rises is maintained wellbelow the top of the trap tray H5. The contact material, removed fromthe bottom of the cyclone separator H2 through the conduit H4, isintroduced into the trap tray H5 to form a slurry with the naphtha.

The naphtha slurry is withdrawn from the trap tray H5 through theconduit 26 by the pump H8. The major portion of the slurry is returnedto the top of the rotating drum lter 96. A small portion of the naphthaslurry is sprayed into the top of the quench condenser through theconduit 2'I and leader 29, as previously described. The flow of naphthaslurry is controlled by the valve 28 to provide sufficient material inthe condenser to wash the condenser tubes free of accumulated contactmaterial. An-

other small portion of the naphtha slurry is fed through the conduit H9to the bottom of the cyclone separator H2 to carry the contact materialthrough the conduit I I4 into the trap tray I I5. This flow iscontrolled by the valve |20.

The Water and entrained contact material are withdrawn from the bottomof the separator 23 through the conduit 3l and discarded. Theconcentration of fines in the water is sufficiently low to permit thediscard of these iines with the waste water, without making the processuneconomical.

As previously described, the fouled contact material is disengaged fromthe oil undergoing treatment in the treating step and brought intocontact with naphtha in one or more solvent washing and filtering steps.For example, the fouled contact material can be introduced to the rotarydrum lter 96 through the conduit 95, wherein it is sprayed with solventnaphtha through the conduit 98. The naphtha passes through the lter in amanner well known in this art. The washed contact material is removedfrom the filter 96 through the conduit IU and conveyer II, andintroduced into the top of the dryer I3 through the conduit I2, aspreviously described.

The specific example shown above, is only intended to be illustrative ofthe invention. The only limitations intended are those presented in thefollowing claims.

What is claimed is:

1. In a continuous contact ltration process wherein adsorbent contactmaterial has become deactivated by liquid phase contact with oil in atreating step, the fouled contact material removed from the oil, Washedwith naphtha and iiltered, and then introduced into a drying zonewherein it is stripped of naphtha and maintained in ebullient motion bysteam introduced into the bottom of said Zone, the method of recoveringthe naphtha and entrained contact material withdrawn from the dryingzone with the eiuent steam therefrom which comprises: separating themajor portion of the contact material from the naphtha and steam in arst separation zone, introducing the naphtha and steam with a minorportion of the contact material still entrained therein into acondensing zone, bringing the naphtha and steam into indirect heatexchange relationship with a cooling fluid in said condensing zone tocondense the naphtha and steam, spraying a small amount of a slurry ofliquid naphtha and contact material into said condensing zone to washthe zone free of accumulated contact material, withdrawing the condensednaphtha and water and contact material admixed therewith from saidcondensing zone, separating the naphtha from the water and admixedcontact material, mixing contact material from the first separation zonewith the condensed and separated naphtha to form a slurry, mixing asmall portion of the slurry with the contact material iirst separatedfrom the naphtha and steam to aid in moving said contact material to thelocus of slurry mixing, introducing another small portion of the slurryinto the condensing zone to serve as the previously described washingmedium, and mixing the remaining slurry with the fouled contact materialwithdrawn from the treating step whereby the major portion of thenaphtha and contact material is returned to the process.

2. In a continuous contact filtration process wherein adsorbent contactmaterial has become deactivated by liquid phase contact with oil in atreating step, the spent contact material removed from the oil, washedwith solvent and filtered, and then introduced into a drying zonewherein it is stripped of solvent and maintained in ebullient motion bysteam introduced into the zone, the method of recovering the solvent andentrained contact material withdrawn from the drying zone with theeliiuent steam therefrom which comprises: separating the major portionof the contact material from the solvent and steam in a rst separationzone, introducing the solvent and steam with a minor portion of thecontact material still entrained therein into a condensing zone,bringing the solvent and steam into indirect heat exchange relationshipwith a cooling uid in said condensing zone to condense the solvent andsteam, spraying a small amount of a slurry of liquid solvent and contactmaterial into said condensing zone to wash the zone free of accumulatedcontact material, withdrawing the condensed solvent and water andcontact material admixed therewith from said condensing zone, separatingthe solvent from the Water and admixed contact material, mixing thecontact material previously separated from the solvent and steam in thefirst separation zone with the separated solvent to form a slurry,mixing a small portion of the slurry with the contact material rstseparated from the solvent and steam to aid in moving said contactmaterial to the locus of slurry mixing, introducing another smallportion of the slurry into the condensing zone to serve as thepreviously indicated Washing medium, and mixing the remaining slurrywith the spent contact material withdrawn from the treating step wherebythe major portion of the solvent and contact material is returned to theprocess.

ERIC V. BERGSTROM. GEORGE J. VISCONTY.

REFERENCES CITED The following references are of record in the file ofthis pat-ent:

UNITED STATES PATENTS Number Name Date 2,102,341 Von Fuchs Dec. 14, 19372,286,815 Kiersted June 16, 1942 2,457,556 Heinemann et al. Dec. 28,1948

